Improvement in steam-engine cut-offs



THOMAS HANsBeow,

DEGEASED, (LUCY A. HANSBROW AND-B. B. REDDING,I'EXEOU `TORS,) OF SACRAIWENTO,.CALIFORNIA.

Leners Patent No. 85,817, dma. .mma/hy `12, 1869.

IMPROVEMENT IN STEAM-NGINE CUT-OFFS.

The Schedule referred to in these Letters Patent and making part of the same.

To all lwhom it concern: v

. Be it known that I, THOMAS HANsBRow, of Sacramento, in the county of Sacramento, and State of Galifornia, have invented a new and useful Improvement in Variable Gut-Ofi' for Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable those skilled "in the art to make and use the same, reference being had tothe accompanying drawings, forming part ot' this specification.

This invention relates to a new andimproved method of controlling, the Aspeed and action of .steam-engines, 'whereby the quantity of steam supplied to the cylinder is proportioned to the work required of the engine; and The invention consists in the combination of the small cylinder and plunger with the cutoff valve, and in the general arrangement of parts, as will be hereinafter more fully described.

Figure 1 represents a sectional elevation of the arrangement, showing the general construction and op' eration of the parts, the section being through the line x z of fig. 2. p

` Figure 2 is a horizontal section oi' fig. l, through the line y y. v

Figure 3 is a horizontal section through the line/Z z of g. 1.

Similar letters of reference indicate corresponding parts.

A is a cylinder, which is in constant communication with the boiler through the steam-pipe B.

Connected with the bottom of this cylinder, is a cylindrical and slightly-conical valv e-seat, C, through the sides of which are parallel and vertical slots or openings, by which steam passes to the interior of the valveseat, and to the steam-pipe D, which conducts the steam to the engine. A

, Fitted to the valve-seat C, and encircling it, is a cylindrical valve, E, with openings which correspond with theopenings in the seat.

This valve is attached to a vertical rod, and the ports for the passage 'of the steam'into the valve-seat are opened and closed by its partial rotation back and forth to a distance equal to the width ofthe openings vor ports in the valve-seat.

The valve-seat C is closed at its top, so that the pressure of steam on the valve is balanced.

Attached to the valve E, is a pitman or rod, y, (seen in fig. 3,) which is connected with a plunger or piston, h. I is a small cylinder, in which the plunger works.

Y The cylinder is in free-communication with the steam in the valve-cylinder A, and the steam -pressure acts upon the plunger, causing the valve E to revolve sufciently to close the openings or portsin the valveseat. Consequently, when not otherwise -acted upon', 'the valve is kept closed b v steam-pressure.

. Air is admitted into the sin-all cylinder I, through orifices, j, so that when the plunger is forced outward by the steam, it acts on an air-cushion.

J is the valve-rodu of E, to which is attached, at right angles therewith, the arm K.

L is the spindle or shaft of the governor.

Attached to the shaft L, and revolving with it, isI

the camM, by which the variable "motion is imparted to the cut-off valve E. v

This cam is'formed of two longitudinal sections of a cylinder, cut parallel with the cylinder upon one side and oblique upon the other, the outer surface or face representing tapering arcs of circles.

The governor-shaft is actuated by gearing or positive motion, and is required to revolve simultaneously with the main engine-shaft.

In' every half revolution of the governor-shaft, one face of the cam strikes the arm K, and this moves theI valve E,'opening the ports and permitting the steam to pass through the valve to the steamechest of the engine.

When this face'of the-cam has passed the arm K, the pressure of steam ou the plunger in the cylinder I revolves the valve, or turns it back and closes the ports, which remain closed until again opened by the otherxface of the arm7 and so on lat each revolution.

The cam, being attached to the governor-shaftL, rises and falls with it, its position beingcontrolled by the position of the governor-balls or speed of the engine.

The face of the cam is perpendicularwith the shaft, and its action on the arm K is to open the ports of the valve to their full extent'instantaneously, and this occurs at the end of each stroke of the engine.

From the shape of the cam, it will be seen that the ports remain open, and the steam 'follows the piston ofthe engine the full length ofthe stroke, or the cutoff-valve port-s are automatically closed by the pressure ofthe steam on the plunger l1, at any point during they stroke, and the steam is allowed to complete its work expaiisively.

This depends upon the power which the engine is, for the moment, required to exert.

If the work to be done requires the full force and4 power of the engine, or pressure of steam in the boiler during the whol length -of the. stroke, .the revolving balls ofthe governor will remain in the position required by such exertion of power.

The face of the cam will hold the arm in the same position, and consequently keep the ports open until the stroke of the ,piston is completed, when the cam releases the arm, and the ports are instantaneously closed by the pressure of steam, as before stated.

' lf there is more steam-pressure than is required for the performance of the work, there will be an increase of motion. The governor-balls will be expanded,'which lowers the cam. The valve-ports are stillopened their whole width at each revolutirm, as before, but they are and desire. to secure by Letters 1. The cylinder I, and plunger 71'i`n combination with the cui-ofi' wtlve :und seint, substantially :ts herein.

shown und descriln-d. i

2. The arrangement of the eiun M, arm K, governorspindle L, valve-scart C, valve E, piston h, small cylinder I, :rnd cylinder' A, as'lierein shown and described.

THOMAS HANSBROW.

Witnesses:

CHARLES J. TORBERT, BENJAMIN B. REDDING. 

